Fred Curtis, KI6GRO
One of the .pdf's is for using the Signal Link on VHF Packet. You have to download another software program that you start up prior to starting up RMS Express.
The other .pdf is for setting up the Signal Link to work with Vara FM which is faster than VHF packet. I am using a Yaesu 897. I have gotten the 897 to work using both VHF Packet and VARA FM using the Signal Link.
There area few of us with the 897 and we have not been able to get the Signal Link to work on HF and RMS Express. I believe that is why you see the HF Go Kits with Pactor III modems in the kit. Pactor Modems will work with the 897. The 857 is similar to the 897
With that being said, a fellow ham as gotten VARA HF to work on the 897 and Signal Link. He found that his upgraded laptop with USB 3.0 connectors was the key. Your mileage may vary.
73 de KI6GRO